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St. Clair County - Illinois 177 Project
Welcome to the Illinois 177 in Mascoutah study page. The Illinois Department of Transportation created this page to share information about the project, provide updates as work progresses and encourage public involvement.
We value your input. To submit comments or questions or to sign up for the project mailing list, visit the Get Involved section below.
Please check back regularly for project updates. Thank you for your interest in the Illinois 177 in Mascoutah study.
IDOT is conducting a preliminary engineering and environmental study for Illinois 177 from County Road to Mine Road in the city of Mascoutah, St. Clair County.
The center portion of Illinois 177, ranging from 18 to 29 feet wide, was originally constructed in 1921. Additional improvements were completed in 1957, 1988, 2002 and 2020. Pavement testing indicates the road has reached the end of its design life and requires reconstruction. A pavement overlay project is planned for 2026 to provide interim improvements until long-term improvements identified through this study are implemented.
The Illinois 177 in Mascoutah study will evaluate:
- Pavement reconstruction
- Intersection improvements
- Bicycle and pedestrian accommodations
- Drainage improvements
Background
IDOT District 8 is studying improvements to the Illinois 177 (Main Street) corridor through the city of Mascoutah from County Road to Mine Road. The proposed length is approximately 1.7 miles.
Within the project limits, Illinois 177 consists of two travel lanes. On-street parking is provided along the north side of the road from Second Street to Independence Street and on both sides for the remainder of the corridor, except between Fifth Street and Seventh Street. Curbs, gutters and sidewalks are present on both sides of the road within the project limits. All intersections within the study area are controlled by stop signs except at Sixth Street, which is controlled by a traffic signal.
The city of Mascoutah is located approximately 28 miles southeast of St. Louis in northeastern St. Clair County. Incorporated in 1837, Mascoutah is primarily a residential community with a population of 8,754, according to the 2020 U.S. Census. The city is near Scott Air Force Base and MidAmerica St. Louis Airport.
IDOT's Three-Phase Project Development Process
Highway improvement projects typically advance through three phases.
Phase I: Preliminary Engineering and Environmental Study (current phase)
Phase I involves evaluating existing conditions, developing and refining improvements alternatives, identifying environmental considerations, and determining potential right of way needs. Phase I is expected to take approximately 36 months.
Phase II: Design and Right of Way
During Phase II, final design plans are prepared and any required right of way is acquired.
Phase III: Construction
Phase III includes construction of the selected improvements.
All three phases of the Illinois 177 project are identified in IDOT’s 2026-2031 Multi-Year Program.
During Phase I, IDOT and its engineering consultant team will:
- Inventory existing conditions, including traffic volumes and crash history
- Identify and document environmental resources
- Develop and evaluate improvement alternatives
Public involvement will occur throughout the study. The outcome of Phase I will be a recommended design that addresses transportation needs while supporting the community’s long-term goals.
Phase I: Preliminary Design & Environmental Study
IDOT and its engineering consultant team will inventory existing conditions, such as traffic data and crash history, and will identify and document environmental constraints as the project moves forward. The Project Study Group (PSG), with input from the public, will also develop and refine improvement alternatives.
The result of the Illinois 177 in Mascoutah Study will be a design for a roadway that addresses identified transportation issues and serves the area’s future needs. Public involvement will take place throughout the project development.
Crash History
A detailed crash analysis will be conducted as part of the study. Safety improvements will be evaluated and incorporated into the project design where appropriate.
The project is using a public involvement program referred to as Context Sensitive Solutions (CSS).
Context Sensitive Solutions
An important part of the bridge study project is public participation. The Illinois Department of Transportation utilizes CSS as a way to continually engage stakeholders in the study. As identified in the Illinois Department of Transportation’s CSS policies, stakeholder involvement is critical to a study’s success. The CSS process seeks to:
- Understand key issues and concerns
- Involve stakeholders early and throughout the study
- Clarify stakeholder roles
- Consider all modes of transportation
- Establish a clear project schedule
- Apply design flexibility when feasible
For more information on IDOT's CSS process, visit Context Sensitive Solutions.
Stakeholder Involvement Plan (SIP)
The goal of the SIP is to outline a program of activities to actively engage stakeholders throughout the Phase I process. The objectives of the SIP are to:
- Identify stakeholders
- Define roles and responsibilities
- Establish outreach timing and methods
- Ensure opportunities for timely input
- Evaluate and adjust outreach efforts as needed
Project Study Group (PSG)
The PSG includes representatives from IDOT, the Federal Highway Administration, and the engineering consultant team. The PSG is responsible for technical analysis and for developing recommendations and decisions for the study
Public Informational Meetings
IDOT will host multiple public informational meetings during the study. These meetings will provide updates on study progress, present alternatives under consideration and offer opportunities for public comment.
Meetings may be held in person, virtually or in hybrid format. Comment forms will be available at meetings and on the project website.
Get Involved
You are encouraged to participate in the Illinois 177 in Mascoutah study.
- Project website: Visit this website regularly for updates.
- Mailing list: To receive newsletters and meeting announcements, contact Matthew Meyer at 618-346-3160 or matthew.meyer@illinois.gov.
- Public meetings: Watch for announcements in local media, libraries, city hall, community centers and on road message boards.
Join the mailing list - submit comments and questions
IDOT welcomes your comments and questions and will respond as promptly as possible.
Contact information collected for this study will be used only for the Illinois 177 in Mascoutah study. If you choose, your name will be added to the mailing list to receive future updates and meeting notices.
For questions or comments, contact:
Matthew Meyer
Illinois Department of Transportation
Phone: 618-346-3160
Email: matthew.meyer@illinois.gov
Or mail:
Illinois Department of Transportation
Attention: Matthew Meyer
1102 Eastport Plaza Drive
Collinsville, IL 62234
Q. Why is this study being conducted?
A. The pavement along the Illinois 177 corridor has been in service since 1921 and has undergone multiple resurfacing projects. The pavement structure has exceeded its service life, and reconstruction is being considered.
Reconstruction provides an opportunity to evaluate broader corridor improvements within the existing right of way, including pedestrian and bicycle accommodations, safety enhancements, drainage improvements, and traffic operations to support future growth.
Q. What are the study limits?
A. The study extends along Illinois 177 from County Road to Mine Road, a distance of approximately 1.7 miles.
Q. Will additional right of way be required?
A. Additional right of way may be required, but this has not yet been determined. IDOT is in the early stages of the preliminary engineering study. Once a preferred alternative is identified and design advances, the need for right of way, if any, will be evaluated.
